In WCDMA communication channel, in addition to the Additive White Gaussian Noise (AWGN), there are various interferences in different environments, so the design of a receiver must take the restraint of interferences into consideration. Under the ideal AWGN environment, a matched filter de-spreader (or called a correlated de-spreader) can be used. In the case of multi-paths interferences, Rake multi-paths diversity de-spread receiver is often used, which needs to estimate the delay and amplitude of the multi-paths. In the channel having narrowband interference, the common used method is to add an adaptive prediction filter in front of the matched filter to estimate the narrowband interference and realize the separation from the wideband spread signals. In the WCDMA system with multi-access interferences, multi-user detection receiver ever received wide attention. It consists of a set of matched filters and a multi-user detector, the typical one is a de-correlated multi-user detector, which has linear complexity and the best ability to suppress the near-far effect. But its disadvantage is needing various information (such as pseudo code, timing, phrase etc.) of all the interference users.
In the method above, the suppression for various interferences is usually performed separately. However, we actually often face with the following two conditions: 1) we may not know which kind of interference environment located in, and also don't clear about the interference parameters; 2) sometimes, there may be various interferences existing at the same time. Under such conditions, the receiver that can suppress one kind of interference may not work normally when under the channel environment in which another kind of interference or various interferences existing simultaneously. There is also a method of combining narrowband notch filter, Rake receiver, and de-correlated multi-user detector. But its disadvantage is that the receiver is extremely complex and even can not be implemented.
The baseband model of BPSK modulation DS/CDMA receiving signal in complex channel environment will be discussed first herein. Spread spectrum modulation and multipath effect use the FIR filter to set up the model. There exists multi access interference, multipath interference, narrowband interference and AWGN. There are K users in the system, the data sequence of each user is dk(n)ε±1, ck and hk are the coefficients of FIR filter. Filter ck completes the function of spread spectrum modulation, with its input being dk(n)δ(n−Tb), provided ck=[ck,0, ck,1, . . . , ck,N-1]T represents the spread spectrum pseudo code sequence of kth user with its value of ±1, then the impulse response of the filter equals to this spread spectrum pseudo code sequence ck, hk represents the effect of the multipath interference. Provided the multipath delay is the integral times of code-chip period Tc, τkTc represents LoS (line of sight) path time delay of kth user, provided the maximum number of multipaths is L, the time delay of each path of kth user is: τkTc, (τk+1)Tc, . . . , (τk+L−1)Tc respectively, and the fading coefficient is denoted by the vector hk=[hk,0, hk,1, . . . , hk,L-1]T, for the user with the number of the multipaths less than L, some elements of hk are zero.
Provided the first user is the expected user, and τk>τ1, (k=2, . . . , K), makemk,l=int[τk+l−τl)/N]qk,l=τk+l−τl−N·mk,l 
The above two equations illustrate how many data code cell periods the lth path of kth user delays relative to the LoS path of the first user, mk,l is the integer part, qk,l is the residue.
If narrowband interference is not considered, the vector of the received signal is represented as:
      x    ⁡          [      n      ]        =                    h                  1          ,          0                    ⁢                        d          1                ⁡                  (          n          )                    ⁢              c        1              +                  ∑                  l          =          1                          L          -          1                    ⁢                          ⁢              [                                            h                              1                ,                l                                      ⁢                                          d                1                            ⁡                              (                                  n                  -                                      m                                          1                      ,                      l                                                        -                  1                                )                                      ⁢                          cf                              1                ,                l                                              +                                    h                              1                ,                l                                      ⁢                                          d                1                            ⁡                              (                                  n                  -                                      m                                          1                      ,                      l                                                                      )                                      ⁢                          cb                              1                ,                l                                                    ]              +                  ∑                  k          =          2                K            ⁢                          ⁢                        ∑                      l            =            0                                L            -            1                          ⁢                                  ⁢                  [                                                    h                                  k                  ,                  l                                            ⁢                                                d                  k                                ⁡                                  (                                      n                    -                                          m                                              k                        ,                        l                                                              -                    1                                    )                                            ⁢                              cf                                  k                  ,                  l                                                      +                                          h                                  k                  ,                  l                                            ⁢                                                d                  k                                ⁡                                  (                                      n                    -                                          m                                              k                        ,                        l                                                                              )                                            ⁢                              cb                                  k                  ,                  l                                                              ]                      +          z      ⁡              (        n        )            
Wherein:cfk,l=[ck,N-qk,l,ck,N-qk,l-1, . . . , ck,N-1,0, . . . , 0]1×NT,cbk,l=[0, . . . , 0,ck,0,ck,1, . . . , ck,N-qk,l-1]1×NT 
The first item in the equation is the LoS path signal of the expected user, the second is the multipath interference generated by the expected user, the third is the multi access interference, the multipath interference generated by multi access user is equivalent to multi access interference, i.e. equivalent to the multi access interference of item (k−1)l, the fourth item is AWGN interference.
Usually, in the base station of WCDMA system, the receiver often adopts correlated receiving or Rake receiving technique, which is the processing method for single user. From the view point of information theory, WCDMA is a MIMO channel, and single user can not make full use of the channel capacity. Multi-user detection can make full use of the time domain information of the multi-user, such as codeword, amplitude, timing, and delay etc., and thus reduce the multipath multi-access interference greatly. Smart antenna technique is on the basis of adaptive antenna and high resolution array signal processing, and makes it possible for the receiver to capture the space domain information of multi-user signal. Such space information includes parameters such as arriving angle, the number of signals, the way of signal polarization, and the relative phase relationship etc.
In order to make full use of the features of the space domain and time domain of the signals, it is necessary to perform space-time associated processing for the signals. The method of space-time associated processing includes the method based on some space-time optimization criterions and the method based on some structure characteristics. In order to make full use of various methods in various conditions, the space-time processing can be combined into software radio architecture, that is to say, space-time associated processing is implemented with software, it is to construct a generalized space-time associated processing method suitable to various channel conditions.
The adaptive smart antenna currently used, such as the ones disclosed in China patent application 01132304 “A Receiving Device with Full Adaptive Smart”, China patent application 01131993 “A Receiving Method and Device with Smart Antenna”, the weight value can be updated by certain criterions according to the changes of the distribution characteristics of signal space, the amplitude and phase of the weight value can be updated freely, when the update algorithm is convergent, this method can make full use of the space features of the expected user signal and interference signal to maximum the SIR (signal interference ratio) of the received signal.
However, there are some key technique problems to be solved when applying the adaptive smart antenna in practice. Wherein, the steadiness and the complexity of the calculation of adaptive beam forming algorithm is one of the problems that limit the development of adaptive antenna. In practical communication, the channel condition is very complex and has the characteristic of time-varying, so it is difficult to use single certain adaptive beam forming algorithm to perform well in all kinds of environments. In the above patents relating to adaptive smart antenna, they either only advance the function that the system realizes without specific implementing method, or provide algorithms that have limitations in application environment. That is also one of the prime reasons why no WCDMA adaptive smart antenna products have appeared till now despite there are many patens and researches on this field.